1. Field of the Invention
This invention relates to a retroreflective paint stripe and a process of applying the paint stripe upon a substantially horizontal surface wherein the paint stripe has reflective particles applied to an upper surface thereof.
2. Prior Art Statement
It is known to make a coating composition which, upon application to a surface, provides reflex-reflective properties to the surface wherein the coating consists of mica flake particles coated with titanium dioxide, glass beads and a binding vehicle. For instance, see the U.S. Pat. No. 3,835,087 to Searight, et al., issued on Sep. 10, 1974.
It is also known to provide a highway and surface marker consisting of a light reflecting pigment coating having essentially the same wet and dry film thickness containing glass spheres embedded therein. For instance, see the U.S. Pat. 2,897,733 issued to Leroy W. Shuger on Aug. 4, 1959.
It is known to measure the retroreflectivity of a reflective layer on a surface by illuminating a portion of the surface at a low angle of incidence with a laser of a specific wavelength, filtering the reflected light at a low angle of observation, collecting the filtered light with a photometer and producing an electrical signal corresponding to the amount of light reflected from the layer. For instance, see the U.S. Pat. No. 4,721,389 issued on Jan. 26, 1988 to Robert Dejaiffe.
It is also known that reflective particles, such as reflective glass beads, on a horizontal surface retroreflect a low percentage of light in the direction of the source of the light at low incident angles and a high percentage of light at angles approaching a perpendicular to the source of light. For instance, see the U.S. Pat. No. 5,571,362 issued on Nov. 5, 1996, to Hachey, et al.
It is known to make small reflective granules by mixing 1-10 parts of glass spheres with one part of a binder composition, solidifying the mixture and then crushing the solidified mixture along lines of cleavage between the binder and the glass spheres to produce the granules. For instance, see the U.S. Pat. No. 3,171,827 to deVries, et al., issued on Mar. 2, 1965.
It is known to make a retroreflective article having a specularly reflective fluid layer, a diffusely reflective layer thereon and then depositing microspheres onto the fluid bi-layer which sink through the diffusely reflective layer and become partially embedded in the specularly reflective layer where in its intended position for use, the article is oriented at least partially vertically. For instance, see the U.S. Pat. No. 5,417,515 issued on May 23, 1995, to Hachey, et al.
The method of providing a traffic surface with both anti-slip and retroreflective characteristics is also known wherein the retroreflective beads are applied to a second coat of paint and are smaller than the anti-slip particles thereby being overshadowed by the anti-slip particles. For instance, see the U.S. Pat. No. 5,380,549 issued on Jan. 10, 1995 to Eric J. Harvison.
Finally, it is known to provide a process of applying a paint stripe having profiling particles embedded in and completely enveloped by the paint and having reflective glass beads scattered upon the upper surface thereof. For instance, see the U.S. Pat. No. 4,856,931 issued on Aug. 15, 1989 to Moses Bollag.